1. Field of the Invention
The present invention relates to an image display apparatus, and more particularly to an apparatus and a method for protecting a screen of a plate type image display apparatus.
2. Background of the Related Art
An image display apparatus is, in general terms, an apparatus for displaying an image signal of a prescribed format that has been transmitted from a source, such as an internal video card, on a display screen. Such display is accomplished through a series of signal processing such as digital sampling and scaling.
Image display apparatuses were originally small sized image display apparatus using a cathode-ray tube. Recently, a digital type display apparatus, using a liquid crystal display (LCD) has been commercialized. It uses as a plate type displaying element appropriate for a large sized image display apparatus according to a tendency toward a large size of the display apparatus in response to the development of the modern technique.
FIG. 1 is a block diagram showing a construction of a related art plate type image display apparatus.
The related art plate type image display apparatus includes a microcomputer 1, which recognizes an input image format according to horizontal/vertical synchronized signals (H-Sync/V-Sync) transmitted from a video card, and outputs a control signal for displaying the signals according to the format. A PLL (Phase Locked Loop) 2 is included for generating a clock pulse for a selected mode according to the control signal of the microcomputer 1, and an A/D converter 3 samples R, G, B image signals transmitted from a main body according to the clock pulse provided from the PLL 2 to convert the R, G, B signals to digital signals.
The apparatus further includes a scaler 4 for converting the digital R, G, B image signals output from the A/D converter 1 to a frame unit to be displayed on a liquid crystal display (LCD) module to transmit according to a signal input timing of the LCD module. A Tx 6 is provided to compress the output signal from the scaler 4 to transmit, and an LCD module 7 is provided to restore the compressed signal output from the Tx 6. The LCD module 7 is further used for driving a liquid crystal to display a screen. An inverter 8 drives a lamp 7c in the LCD module 7.
Further, the I-CD module 7 includes an Rx 7a for restoring the compressed signal output from the Tx 6, a TFT control part 7b for driving the liquid crystal according to the signal input from the Rx 7a to control the screen to be displayed, and the lamp 7c.
The operation of the related art plate type image display apparatus will next be described.
First, the microcomputer 1 recognizes a resolution of the horizontal/vertical synchronized signal transmitted from the video card as the signal is input. The microprocessor also controls the driving of a power supply and the lamp.
The microcomputer 1 outputs a control signal to the PLL 2 for setting a sampling clock used by the A/D converter 3 to convert the input image signal into a digital signal. The resulting resolution corresponds to a resolution preset by a user and a resolution supported by the plate type image display apparatus.
The PLL 2 sets a sampling clock per mode according to a control signal output from the microcomputer 1, and the A/D converter 3 samples the analog R, G, B image signals transmitted from the main body according to the clock pulse provided from the PLL 2. The analog R, G, B signals are thus converted to digital R, G, B signals.
For example, the digital sampling for an XGA signal is performed by generating a sampling clock of 65MHz according to a horizontal synchronizing signal timing for sampling the XGA image signal so that 8 bit digital R, G, B image signals are output.
The scaler 4 performs a signal processing of the digital R, G, B image signals output from the A/D converter 3 according to the control signal of the microcomputer 1 by a frame unit, and a frame buffer memory 5 stores an output from the scaler by the frame unit.
The Tx 6 then transmits the digital R, G, B image signals stored in the frame buffer memory after compressing.
The LCD module 7 drives the liquid crystal to display the screen by applying an output signal from the scaler 4 to the TFT control part 7b or the signal compressed by the Tx 6 and received via the Rx 7a to the TFT control part 7b. 
Further, the inverter 8 drives the lamp 7c in the LCD module 7 according to a control signal of the microcomputer 1. That is, the LCD module 7 and the lamp 7c are turned off only when the user turns off the power supply. A chlorosis is otherwise generated when an abnormal horizontal/vertical synchronizing signal is input.
The plate type image display apparatus of the related art as describe above has several disadvantages. For example, the plate type image display apparatus can not recognize data, power supply, and synchronizing signals applied to the plate type display apparatus in an abnormal sequence. If such an abnormal signal is applied, the LCD module may be damaged. Further, when abnormal data is input, the whole screen of the plate type image display apparatus is displayed white due to the chlorosis since the abnormal data input can not be recognized.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.
An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
Another object of the present invention is to provide an apparatus and a method for protecting the screen of an image display apparatus that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.
Another object of the present invention is to detect abnormal input data.
Another object of the present invention is to control the driving of at least one of the power supply and the lamp in a display apparatus.
A further object of the present invention is to display a normal screen on an image display by compensating errors.
A further object of the present invention is to prevent chlorosis in a display module.
To achieve at least these and other advantages in whole or in parts there is provided an apparatus for protecting a screen of a plate type image display apparatus including a liquid crystal display (LCD) module and an inverter, comprising an A/D converter for converting an analogue image signal into a digital image signal according to a sampling clock, a scaler for converting digital R, G, B image signals output from the A/D converter into a frame unit able to be displayed on the LCD module to transmit according to a signal input timing of the LCD module, a frequency detecting part for detecting an output frequency of a signal output from the scaler; and a microcomputer for controlling power supply to the LCD module and the inverter by determining whether the output frequency detected by the frequency detecting part is within a predetermined preset frequency range.
To further achieve at least the above described advantages in whole or in parts, there is provided a method for protecting a screen of a plate type image display apparatus including an A/D converter, a scaler, an inverter and a liquid crystal display (LCD) module includes determining whether an output frequency of the scaler is within a predetermined preset frequency range or not, turning off power supply of the inverter and the LCD module and initializing the A/D converter and the scaler if the detected output frequency is not in the predetermined preset frequency range, and turning on the power supply of the inverter and the LCD module and displaying a normal screen if the detected output frequency is in the predetermined preset frequency range.
To further achieve at least the above described advantages in whole or in parts, there is provided an image display apparatus that includes a scaler to convert image signals into a frame unit to be displayed on an LCD module, and to transmit the signals corresponding to a signal input timing of the LCD module, a frequency detector detect an output frequency of the scaler, and a microcomputer to determine whether the output frequency detected by the frequency detector is within a prescribed frequency range, and to control a power supply for the LCD module.
To further achieve at least the above described advantages in whole or in parts, there is provided a method for protecting a screen of an image display apparatus that includes determining whether an output frequency of a scaler is within a prescribed frequency range, turning off a power supply of a LCD module and initializing the scaler if the detected output frequency is not within the prescribed frequency range, and turning on the power supply of the LCD module and displaying a normal screen if the detected output frequency is within the prescribed frequency range.
To further achieve at least the above described advantages in whole or in parts, there is provided an image display apparatus that includes a video signal processor to receive a video signal of a first format and output a video signal of a second format, a formatter to format the signal of the second format for displaying an output screen, an output module to provide the formatted signal from the formatter to the output screen, and a control unit, which detects the frequency of the formatted signal from the formatter, and prevents the operation of the output module if the frequency is outside of a prescribed range.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.